Edge Wrapping of cover sheet for panel

ABSTRACT

A process and apparatus for simultaneously securing opposite parallel edge flaps of a flexible cover sheet to opposite parallel edge faces of a wall panel. A pair of wiping devices move downwardly and wipe the edge flap against the edge faces and transversely tension the cover sheet. Top sweep devices move down into holding contact with the cover sheet adjacent the parallel edge faces to maintain the transverse tension in the sheet. The edge flaps are then deflected and adhesive applied to the edge faces and back surfaces of the edge flaps. The wiping devices then again wipe the flaps downward into pressed contact with the edge faces to create an adhesive securement therewith.

FIELD OF THE INVENTION

This invention relates to an apparatus and process for securing a thinflexible covering sheet to a side of an upright wall panel, includingtensioning of the sheet and securing of sheet edge flaps to panel edgefaces.

BACKGROUND OF THE INVENTION

Wall systems defined by upright space-dividing panels are widelyutilized in offices and the like to divide large open areas into smallerwork spaces. Such panels, which may be of floor-to-ceiling height or oflesser height, are typically prefabricated employing a rigid ring-shapedframe surrounding a suitable core structure, with a thin flexiblecovering sheet positioned over the large exterior side surface of thepanel and edge flaps of the covering sheet being wrapped around andsecured to edge faces of the frame. The covering sheet usuallyconstitutes a thin flexible fabric, vinyl or foil-like material, anddefines the exposed side surface of the assembled wall panel.

In a typical wall panel of the aforementioned type, it is conventionalto secure the covering sheet to the frame by inserting the cover sheetedge flaps into grooves or channels which extend lengthwise along theedge faces of the frame, with the flaps being held within the channelsby an elongate retaining element, often referred to as a spline. Theelongate retaining element is generally of paper or elastomeric materialso that it can be compressed into the channel and wedgingly hold theedge flap in engagement therein. This construction is and has beenwidely used since it facilitates removal and replacement of the coversheet when desired. This securement process, however, is difficult andlabor intensive inasmuch as the spline is typically progressivelyinserted lengthwise along the channel by a manually manipulated toolwhich requires significant manual manipulation and introduces variationsinto the assembly process with respect to the overall quality of thesecurement and the tensioning of the cover sheet on the assembled wallpanel.

An example of a known wall panel employing a construction similar tothat described above is illustrated by U.S. Pat. No. 5,606,836, owned bythe Assignee hereof.

While the above described technique has and continues to be successfullyutilized in many situations, nevertheless it has been discovered thatthe technique of employing a spline-and-groove securing techniqueresults in additional complications when dealing with newer types offabric cover sheets currently in use, specifically cover sheets orfabric sheets which have a loose weave pattern and/or employ plasticfibers as such fabrics are more easily distorted and have a moreslippery texture, whereby application of the fabric and the securementthereof using the spline technique induces additional problems withrespect to either slippage of the fabric and/or distortion of the fabricduring the assembly process. These slippage and/or distortion problemscan significantly and adversely impact the overall visual and henceaesthetic appearance of the wall panel.

Accordingly, it is an object of this invention to provide an improvedapparatus, and related process, which facilitates and at leastsignificantly automates the tensioning of a flexible cover sheetpositioned over a large exterior side surface of a wall panel structure,and which effects securement of edge flaps associated with the coversheet to the edge faces of the wall panel frame.

It is a further object of the invention to provide an improvedapparatus, and process associated therewith, for permitting initialtensioning of the cover sheet by initially folding and wiping the edgeflaps into pressed contact with edge surfaces of the frame to effectinitial tensioning of the sheet, preferably followed by subsequentadditional tensioning by engaging the cover sheet with sweeping bladesin close proximity to the panel edges and then sweeping the bladesoutwardly toward the respective edges, followed by subsequentmanipulation of wiping blades which folds the edge flaps upwardly topermit adhesive to be applied to the back sides thereof, after which thewiping blades wipe the edge flaps downwardly into contacting engagementwith the edge surfaces of the frame to effect adhesive securementtherewith. With this improved apparatus, and process, the edge flaps canbe secured directly to a flat edge surface associated with the frame, orin an alternative arrangement a portion of the edge flap can be insertedinto a groove associated with the frame edge face so as to provide aconstruction which permits field-replacement of the covering sheet andmounting of a new covering sheet and securement thereof in aconventional manner utilizing a spline insertable into the groove.

In the apparatus of the present invention, as aforementioned, there isprovided an upwardly-facing working station for accommodating ahorizontally-oriented wall panel structure thereon, which wall panelstructure has a flexible covering sheet positioned to extend wholly overthe upwardly-facing side surface of the wall panel structure and hasflexible edge flaps which extend along each edge of the wall panelstructure and protrude outwardly therefrom by a predetermined distancewhich is less than the thickness of the wall panel structure. Thecovering sheet is not attached to the upward-facing side surface of thewall panel structure to permit suitable movement of the covering sheetduring tensioning. A cover attaching arrangement is movably supportedabove the working station, and includes a pair of flap wiping assembliespositioned above opposite side edges of the wall panel assembly. Thewiping assemblies each include an elongate wiping blade, preferably ofan elastomeric material, which when moved downwardly contacts the edgeflap along the entire lengthwise extent of the wall panel edge so as topress the flap downwardly along the respective edge surface. The coverattaching arrangement also includes a pair of sweeping devicespositioned in close proximity to the respective wiping assemblies anddisposed over the working station in close proximity to the oppositeedge faces of the wall panel structure. These sweeping devices eachinclude a horizontally elongate sweep blade, preferably of anelastomeric material, which is moved downwardly into engagement with theupward-facing cover sheet close to and generally parallel with theadjacent edge face, and then is moved outwardly to a position generallyat the edge surface to effect final tensioning and holding of thecovering sheet. The wiping blades are then moved upwardly to deflect theedge flaps upwardly against a suitable support surface associated withthe respective sweeping device, after which a suitable adhesiveapplicator, such as a spray device, applies a suitable adhesive to theexposed back side of the upwardly-deflected edge flap, and also appliesadhesive to the exposed edge surface of the panel frame. Thereafter thewiping blades are disengaged from the edge flaps, whereupon the edgeflaps fold or fall downwardly so as to hang adjacent the edge surfaces.The wiping blades are then moved downwardly and effects pressingengagement of the edge flaps into adhesive contact with the opposedfacing surfaces on the edge frames of the wall panel structure.Thereafter the wiping and sweeping blades are disengaged from the fabriccovering and returned to their initial positions to permit initiation ofa further securement operation.

In the aforesaid operation, the edge frame of the wall panel structurecan be provided with a conventional groove extending lengthwise alongthe edge face, and the edge flap can be sized to include suitablematerial for accommodation within the edge groove during the securementprocess. In such case the wiping assembly is provided with a tuckingblade disposed in close proximity to the elastomeric wiping blade. Thetucking blade is activated, after the wiping blade has wiped downwardlyand adhesively contacted the edge flap against an opposed flat surfaceon the edge frame, so as to insert a lower free end portion of the edgeflap into the groove. This groove preferably has adhesive on thesurfaces thereof as applied during the adhesive application step, andthis, coupled with the adhesive on the back side of the edge flap,cooperates to provide additional securement of the edge flap to the edgeframe of the panel structure.

The apparatus and process of the present invention, as well as theaforementioned and other objects, purposes and advantages of thisinvention, will be apparent upon reading the following specification andinspecting the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an apparatus for securing edge flaps ofa covering sheet to a wall panel structure, which apparatus in FIG. 1illustrates a wall panel structure being fed into one end of theapparatus for disposition at the working station thereof.

FIG. 2 is an enlarged perspective view of the apparatus shown in FIG. 1.

FIG. 3 is a front elevational view showing the input end of theapparatus of FIG. 2, and showing the sweeping and wiping devices intheir retracted inactive positions.

FIG. 4 is a view corresponding to FIG. 3 but showing the sweeping andwiping devices in their lowered activated positions.

FIG. 5 is a diagrammatic line drawing showing an input-end elevationalview similar to FIG. 3 wherein the wiping and sweeping devices are intheir raised inactive positions, prior to their being engaged with aworkpiece or wall panel structure disposed at the working station.

FIG. 6 is a diagrammatic line drawing, on an enlarged scale, showing thesweeping and wiping devices associated with the right side of theapparatus shown in FIG. 5.

FIG. 7 is a diagrammatic line drawing taken generally along line 7-7 inFIG. 5.

FIG. 8 is a fragmentary elevational view showing the relationshipbetween the sweeping and wiping devices (on the left side of theapparatus) and their cooperation with the related edge of the workpiecesupported at the working station, the sweeping and wiping devices beingillustrated in their raised inactive or “start” positions.

FIG. 8A is an enlarged fragmentary diagrammatic view showing theleft-side sweeping and wiping devices in an intermediate operationalposition wherein the wiping blade engages the upper edge of theworkpiece for wiping the edge flap downward of the edge face.

FIG. 9 is a view similar to FIG. 8 but showing the wiping device in apartially lowered position wherein the wiping blade has engaged andeffected initial tensioning of the cover sheet and is engaged againstthe edge frame of the panel, and wherein the sweeping blade has beenmoved downwardly and then moved outwardly to the panel edge to effectfinal tensioning of the cover sheet.

FIG. 10 is a view similar to FIG. 9 but showing the wiping blade loweredso as to disengage the edge flap, and the sweeping blade maintained incontacting engagement with the cover sheet at the wall panel edge.

FIG. 11 corresponds generally to FIG. 10 in that the sweeping blade isstill engaged with the cover sheet, but the wiping blade has been raisedupwardly above the wall panel structure, causing the edge flap to bedeflected upwardly and held against an exposed side face of the sweepingblade support, thereby exposing the back side of the edge flap to permitan adhesive to be applied thereto and to the exposed edge surface of thewall panel frame.

FIG. 12 is a diagrammatic plan view of a wall panel structure having aflexible covering sheet disposed so as to extend over one large sideface thereof, with the covering sheet having flexible edge flaps whichextend along each edge of the wall panel structure and protrudeoutwardly so as to be folded downwardly and secured to the respectiveedge surface of the wall panel structure.

FIG. 13 is an enlarged sectional view taken generally along line 13-13in FIG. 12 and diagrammatically illustrating a typical construction ofthe wall panel, including the frame structure and the provision of asecuring groove in the frame edge face for securement of the edge flaptherein by means of a retaining spline.

Frames 14 and 15 are views similar to FIG. 13 but showing the securementof the cover sheet edge flap in accordance with the present invention.

Certain terminology will be used in the following description forconvenience and reference only, and will not be limiting. For example,the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” willrefer to directions in the drawings to which reference is made. Thewords “inwardly” and “outwardly” will refer to directions toward andaway from the geometric center of the apparatus or panel, and designatedparts thereof. The word “front” when used in reference to the wall panelwill refer to the exterior side thereof which faces outwardly when thepanel is mounted in its normal upright position, and the word “front”when used in reference to the apparatus will refer to the side of themachine which is used for inputting the wall panel structure to theworking station, which side is designated by the arrow “IN” in FIG. 2.Said terminology will include the words specifically mentioned,derivatives thereof, and words of similar input.

DETAILED DESCRIPTION

Referring initially to FIGS. 12 and 13, there is illustrated a knownconstruction for a wall panel structure 11, which construction issimilar to that illustrated in the aforementioned '836 patent. The wallpanel structure 11 includes a substrate defined primarily by a generallyrectangular ring-shaped rigid frame 12 formed by elongate frame elements13 which extend along each edge of the panel and, at their adjacentends, are rigidly joined to define the corners of the panel. Theinterior of the ring-shaped frame is typically provided with a suitableand conventional core structure 14 therein. The wall panel 11 in theillustrated arrangement has the sides thereof defined by generallysheet-like or plate-like side members 15 which, in the illustratedembodiment, are constructed similar to dry wall sheets although othersimilar constructions are obviously suitable. The sheets 15 are seatedwithin and on a boundary flange 16 which defines the outer surface forthe edge face of the panel. The flange 16 joins to a further wall orflange 23 which protrudes inwardly and functions as a rear support wallfor the side member 15.

The wall panel substrate has a thin flexible covering sheet 17positioned to extend over the entire exterior side face 19 thereof. Thiscovering sheet 17 additionally has edge portions or flaps 18 whichextend lengthwise along the full length of the respective edge of thepanel frame and which protrude beyond this edge by a predeterminedextent or distance which is less than the thickness of the wall panelsubstrate. The edge flap 18 is flexible and, during typical assembly, isfolded downwardly to overlap the boundary flange 16 of the frame. Inaddition, the illustrated frame has a depressed channel structure 21located inwardly of the flange 16 and defining an outwardly openinggroove or channel 22 into which a free end part of the edge flap 18 isinserted, as illustrated in FIG. 13. The edge flap is retained in thesecuring groove 22 by a deformable retaining element or spline 24 whichis typically manually and progressively inserted into the groove 22along the length thereof, and which expands to effect gripping of theedge flap within the groove.

As illustrated by FIG. 12, the flexible covering 17 is preferablyprovided with cutouts or recesses 25 at the corners so as to minimizethe amount of excess fabric material at the corner of the frame, andfacilitate the securement of the edge flaps to the frame.

When the cover 17 is secured to the wall panel substrate 11 so as tocomplete overall assembly of the wall panel, the covering sheet 17 isfree of direct attachment to the underlying side surface 19 of the wallpanel substrate. Rather, the covering sheet 17 is attached solelythrough the attachment of the edge flaps 18 to the exposed edge faces ofthe frame members.

In accordance with the present invention, the securement of the coversheet to the frame is such as to permit elimination of the retainingspline 24 illustrated in FIG. 13. Rather, the edge flap can beadhesively secured solely to an exposed surface associated with andextending lengthwise along the edge of the wall panel frame, such as theflange 16 as shown in FIG. 14. If necessary or desired, however, theedge flap 18 can be sized to include a portion adjacent an outer edgesufficient to be inserted into a groove or channel similar to the groove22 (FIGS. 14 and 15), with this portion of the edge flap beingadhesively secured to the inner wall of the groove. The apparatus andprocess for accomplishing this desirable construction will now beexplained with reference to FIGS. 1-11.

Referring initially to FIGS. 1-5, there is illustrated an apparatus 30according to the present invention for effecting tensioning of theflexible cover sheet and securement of the cover sheet edge flaps toedge surfaces of the wall panel frame in accordance with the briefdescription presented above. More specifically, the apparatus 30cooperates with a horizontally-oriented wall panel 31 (herein referredto as a “workpiece”) which corresponds generally to the construction ofthe wall panel described above, and which in the illustrated embodimentis disposed on a support sheet 32 to facilitate movement of theworkpiece into and out of the apparatus 30.

The apparatus 30 includes a frame arrangement 35 having a lower frame 36which mounted thereon a generally upwardly-opening U-shaped upper frame37, the latter having right and left upright side frames 38 which aresidewardly spaced apart and are rigidly joined by generally horizontalcross frame members 39. The side frames 38 include generally paralleland horizontal elongate top frame members 41 which are rigidly joinedtogether by a top frame structure or beam arrangement 42 extendingtransversely therebetween, the latter constituting a fixed uppersupport. This upper support 42 is spaced upwardly above a generallyhorizontally enlarged working station 43 defined between the right andleft side frames 38 and disposed generally at the elevation of thehorizontal cross frame members 39. The working station 43 functions toreceive and support the workpiece 31 for permitting proper attachment ofthe cover sheet edge flaps thereto, as explained hereinafter. To definethe working station 43, any suitable conventional platen or conveyingsystem, such as conveying belts, may be utilized.

The overall apparatus 30 includes a cover attaching arrangement 44 whichis generally supported by and positioned downwardly below the fixedupper support 42 so as to be disposed between the side frames 38 andgenerally above the working station 43.

The cover attaching arrangement 44 includes a first mechanism 46 whichfunctions to engage the up-facing cover sheet 17 at locations close tobut inwardly from parallel edge faces of the workpiece frame to effectoutward sweeping and hence tensioning of the cover sheet. This firstmechanism 46 is herein referred to as the “sweep” mechanism.

Cover attaching structure 44 also includes a second mechanism 47, hereinreferred to as a “wiping” mechanism, the latter effecting engagement andmanipulation of the cover sheet edge flaps 18 to carry out multiplefunctions, including tensioning of the cover sheet, positioning of theflaps to permit application of adhesive to the back side thereof, andpressing of the adhesive-coated flaps against edge surfaces on paralleledge faces of the frame to effect attachment of the cover sheet thereto,all as explained hereinafter.

The sweeping and wiping mechanisms 46 and 47, respectively, are bothmounted on the upper frame 37 for vertical movement generally parallelto the center vertical plane 49 which extends from the input to the exitor output end of the apparatus. These mechanisms 46 and 47 includerespective sweeping blade and wiping blade assemblies which are disposedsymmetrically on oppose sides of the central vertical plane 49 so as toconstitute right and left side assemblies which respectively cooperatewith the right and left edges of the workpiece, which edges extendhorizontally in parallel relationship to the center plane 49, as will beapparent from the following description.

As illustrated by FIGS. 3-6, the sweeping mechanism 46 includes agenerally horizontally enlarged movable lower support 51 spaceddownwardly from the fixed upper support 42 and defined by a plurality ofhorizontally elongate plate members 52 which extend transversely insidewardly spaced relation and which are rigidly joined together by endangles 53. A top connecting plate 54 extends over and rigidly joins theplates 52.

The lower support 51 is supported by and connected to a driving unit 55which includes a pair of conventional pressure cylinders 56 mounted onthe fixed upper support 42, and which have the extendible pressure rodsthereof connected to a cross bar 57. The latter in turn rigidly joins toupper ends of a pair of vertical support rods 58 which extend downwardlyand have lower ends rigidly joined to the lower support 51.

The vertical movement of lower support 51 is suitably guided by aplurality of generally parallel sliding guide rods 59 which have theirlower ends anchored to the support 51, with upper ends of these guiderods 59 being slidably guided through guide blocks 61 which are securedto the upper support 42.

The sweep mechanism 46 includes a pair of sweeping devices 62 foreffecting sweeping and clamping of the flexible cover sheet 17 whichextends over the upward-facing side of the workpiece 31 disposed at theworking station 43. These sweeping devices 62 constitute right and leftdevices relative to the vertical center plane 49 inasmuch as they aresubstantially mirror images of one another relative to this plane, andare equally spaced outwardly on opposite sides of the central plane soas to be disposed in close proximity to but upwardly above therespective right and left frame elements (i.e. edge faces) associatedwith the workpiece 31 disposed at the working station 43.

Each sweeping device 62 includes a generally horizontally elongatebar-like carrier 63 which extends parallel to the center plane 49, andis horizontally elongate through a length which corresponds to andgenerally at least slightly exceeds the length of the correspondingpanel edge frame member disposed downwardly therefrom. The carrier 63mounts thereon a sweeping member 64, generally referred to as a blade,the latter extending lengthwise along the carrier 63 and protrudingdownwardly and terminating in a downwardly cantilevered tip end 65which, when the sweeping device 62 is in its raised start or inactiveposition, is disposed over and spaced upwardly a small distance abovethe flexible cover sheet 17 associated with the workpiece 31. Thesweeping blade 64 is preferably constructed of an elastomeric materialso as to have the ability to resiliently deform and create a resilientengagement with the cover sheet so as to not significantly harm thelatter.

The carrier bar 63 and the wiping blade 64 mounted thereon are movablehorizontally through at least a small extent due to their being carriedon the free ends of piston rods associated with a pair of conventionalpressure cylinders 66, the latter being disposed in generally parallelrelationship lengthwise of the carrier bar. These cylinders 66, whenactivated, are capable of moving the carrier 63 and the blade 64 thereonhorizontally sidewardly generally transverse to the center verticalplane 49.

Each pressure cylinder 66 is carried on a mounting member 67, the latterhaving a ball slide unit fixed thereto and horizontally slidably engagedon an elongate slide rail 69 fixed to the underside of the support 51and extending horizontally therealong in generally perpendicularrelation to the center vertical plane 49. This slidable mounting enablesthe sweep devices 62 to be slidably displaced so as to be moved towardor away from the central plane 49 to adjust the sideward spacingtherebetween corresponding to the width of the workpiece 31 disposed atthe working station 43.

Considering now the wiping mechanism 47, it includes a movableintermediate support 71 disposed horizontally between the side frames 38and positioned vertically between the fixed upper support 42 and themovable lower support 51. This intermediate support 71 includes a mainsupport plate or beam 72 which extends generally transversely betweenthe right and left side frames 38, and opposite ends of the support beam72 have ball slide units 73 carried thereon which in turn are engagedfor vertical movement along elongate vertical slide rails 74, the latterbeing fixed to frame plates 75 secured to the respective side frames 38.

The intermediate support 71 is vertically movable relative to the uppersupport 42, and independently of the lower support 51. The movement ofthe intermediate support 71 is controlled by a drive system 76 includinga screw-type drive shaft 77 which is supported on and extendshorizontally along the upper support 42 in generally perpendicularrelationship to the center vertical plane 49. This drive shaft 77 isrotated by a suitable drive device such as a reversible drive motor 78.The drive shaft 77 has screw portions adjacent opposite ends, whichscrew portions are of opposite hand and are respectively engaged withconventional jack-type drive screw units 79. Each screw section of thedrive shaft 77 is engaged with a nut associated with the respectivedrive screw unit 79, which nut in turn cooperates with an output screwshaft 81 associated therewith to effect vertical displacement of theshaft 81. The shaft 81 in turn has a lower end thereof coupled to theintermediate support 71 so as to effect desired vertical displacementthereof, which displacement is slidably guided and controlled by thecooperation between the slide units 68 and the slide rails 69.

Considering now the wiping mechanism 47, it includes a pair of wipingassemblies 82 which are carried on and project downwardly from theintermediate support 71, constituting right and left units inasmuch asthey are symmetrical to one another and symmetrically disposed onopposite sides of the center vertical plane 49. The wiping units 62 arepositioned generally above and adjacent the respective edge faces of theworkpiece 31 disposed at the working station 43, and are positioned sothat they are disposed adjacent and slightly outwardly of therespectively adjacent sweeping device 62.

Each wiping assembly 82 includes an elongate bar-like carrier 83 whichextends horizontally generally parallel to the center vertical plane 49and throughout at least the length of the adjacent horizontal edge faceof the workpiece. This carrier 83 mounts thereon a wiping member 84,herein referred to as a blade, which projects horizontally inwardly andterminates at a tip end 85 which is cantilevered generally horizontallyinwardly toward the central vertical plane 49. This wiping blade 84 ispreferably constructed of an elastomeric material having substantialresiliency so as to permit it to resiliently act on and contact the edgeflap of the fabric cover sheet without causing any significant damagethereto.

The elongate carrier 83 and the wiping blade 84 extending lengthwisetherealong are mounted to the lower ends of a pair of verticallyelongate supports or columns 86 which are disposed in spacedfront-to-back relationship on the apparatus, and which project upwardlyin parallel relationship for connection to the intermediate support 71.Each upright support 86, at its upper end, has a slide unit 87 slidablyengaged with a horizontally elongate slide rail 88 which is fixed to theunderside of the intermediate support 71 and extends transversely so asto be elongated generally perpendicular to the center vertical plane 49.This slidable mounting enables the right and left wiping assemblies 82to be horizontally moved inwardly or outwardly relative to the centervertical plane 49 so as to adjust for different widths of workpieces.

The bar 84 as carried on the lower ends of the support columns 86includes a horizontal slide connection defined by a slide unit 89carried on the lower end of the support column and engaged with ahorizontally elongate slide rail 91 which is mounted on and extendstransversely of the blade carrier 83. This connection between slide 89and slide rail 91 enables the blade carrier 83 and the blade 84 mountedthereon to be horizontally displaced generally transverse to the centralvertical plan 49 through at least a small distance. To permit suchsideward horizontal displacement of the carrier 83, the latter isconnected to the piston rods of a pair of pressure cylinders 92 which inturn are carried on the support columns 86, whereby energization ofpressure cylinders 92 enables the carrier 83 to be horizontallysidewardly displaced inwardly or outwardly relative to the center plane49.

In situations where the edge flap 18 of the fabric cover 17 is sized soas to have a part thereof inserted into a channel or groove in themanner illustrated by FIG. 14, then the carrier 83 also mounts a movableinserter or plunger 93 which is supported for horizontal displacementsidewardly (i.e., generally transversely with respect to the centerplane 49), whereby a tip end 94 of the inserter 93 can be movedhorizontally inwardly to permit insertion of the lower portion of theedge flap 18 into a groove or channel, such as groove 22 illustrated byFIG. 14.

The inserter 93 extends horizontally lengthwise along the carrier 83,and is selectively horizontally movable between extended and retractedpositions by suitable drive devices, such as one or more pressurecylinders 95 which are carried on the carrier 83 and have the pistonrods thereof coupled to the inserter 93 for controlling the horizontalsliding movement thereof.

To control sideward positioning and spacing of the right and left wipingassemblies 82 in accordance with the width of the workpiece 31 disposedat the working station 43, the carrier 83 associated with each wipingmechanism 82 has, as illustrated in FIG. 7, a drive arm 97 fixed theretoand projecting vertically upwardly thereof. This drive arm 97 at itsupper end has a nut part which is threadably engaged with a threadedscrew section of a drive shaft 98. This drive shaft 98 extendshorizontally along the underside of the intermediate support 71 ingenerally perpendicular relationship to the center plane 49, and isrotatably supported by appropriate support bearings 99. The drive shaft98, on opposite sides of the central plane, is provided withopposite-hand threads so that engagement with the drive arms 97associated with the right and left wiping device 62 causes these devicesto simultaneously and synchronously move either inwardly or outwardlyrelative to the center plane 49, depending upon the direction of shaftrotation. The rotation of shaft 98 is accomplished by any conventionalsuitable drive device, such as a reversible drive motor 101 asdiagrammatically illustrated in FIG. 6.

To simultaneously adjust and control the positioning of the sweepingdevices 62 in correspondence with the wiping devices 82, the supportcolumn 86 associated with each wiping device has a vertically elongateslide rail 103 fixed thereto, and the latter is engaged by a slide unit102 which is fixed to the mounting member 67 of the respectivelyadjacent sweeping device 62. Hence, whenever the sideward positioning ofthe wiping units 82 is adjusted, a corresponding sideward adjustmentoccurs in the positioning of the sweeping units 62, thereby maintainingthe desired sideward positional relationship between each wiping device82 and is respectively adjacent sweeping device 62.

The overall cover attaching arrangement 44 also preferably includes, asillustrated in FIG. 6, an adhesive applicator arrangement 105 associatedwith each of the right and left sides of the apparatus, and specificallyassociated with each of the right and left sweeping devices 62. Theadhesive applicator 105, as illustrated diagrammatically in FIG. 6,includes a support bracket arrangement 106 which is fixed to andprojects downwardly from the mounting plate 67 of the sweeping device,with a pair of such brackets 106 preferably being disposed adjacent eachend (i.e., adjacent both the inlet and outlet end) of the apparatus.These brackets 106 mount thereon a horizontally elongate drive unit 107,such as a conventional horizontally elongate rotatable screw whichcooperates with a traveling nut movable lengthwise along the screw independence on the direction of screw rotation. The traveling nut of thisconventional screw arrangement in turn is coupled to and carries amoving arm 108 which, at its outer end, carries a conventional sprayhead or nozzle 109, the latter being connected through suitable hosesand the like (not shown) to a conventional pressurized spray systemwhich in turn can be suitably mounted on the frame of the overallapparatus, such as on the lower frame structure. The spray nozzle 109 ispositioned so that the discharge orifice thereof is directed in closeproximity to but spaced outwardly from the adjacent upper edge of theworkpiece edge frame, and the nozzle preferably is configured to emit avertical fan-shaped spray pattern. Thus, the nozzle, when movedlengthwise along the workpiece, emits a fan-shaped spray which iscapable of applying an adhesive coating to the adjacent exposed edgesurfaces of the workpiece, such as the flange 16 and the interior of thegroove 22 illustrated in FIG. 14. This spray pattern also preferablyextends upwardly a sufficient amount so as to apply adhesive to theexposed back side of the edge flap 18 when the latter is in the raisedposition illustrated by FIG. 11, as explained hereinafter.

The support arm 108 carrying the spray nozzle 109 thereon is preferablymovable between extreme end positions, such as a first end positiondiagrammatically illustrated by the solid-line position of the nozzle109 in FIG. 7, and the other extreme end position illustrated by thedotted-line position of the nozzle 109 in FIG. 7. This enables thenozzle to traverse the full length of the cover sheet edge flap, whileat the same time the nozzle can be positioned outwardly beyond the endsof the wiping carrier bar 83 so as to not interfere with the desiredvertical movement thereof during a normal operational sequence.

The operation of the apparatus 30 in accordance with the presentinvention will now be briefly summarized.

Since the apparatus 30 will typically be utilized to permit sequentialprocessing of numerous like-sized panels, the wiping devices 82 areinitially sidewardly positioned at the desired sideward spacing inaccordance with the desired panel width by suitable activation of themotor 101 and drive shaft 98. This in turn causes automatic widthadjustment and hence ensures proper sideward spacing of the sweepingdevices 62 due to their positional control by the slide assemblies102-103.

The workpiece which is fed into the apparatus will, of course, include awall panel substrate having the flexible cover sheet 17 disposed overthe upward-facing side surface thereof, the cover sheet beingnon-attached to the wall panel substrate and having edge flaps 18 whichprotrude outwardly beyond the edge faces of the substrate frame.

The workpiece 31 is inserted, either manually or more preferablyautomatically by a suitable conventional conveying system, into theinput end of the apparatus 30, with the workpiece being positioned atthe working station 43 by suitable and conventional guides, stops and/orposition sensors, all of which are well known. With the workpieceproperly positioned at the working station 43, and the respectivesweeping and wiping mechanisms 46 and 47 in their retracted startpositions substantially as illustrated by FIGS. 3, 5, 6 and 8, theassembly process is then formally initiated.

To initiate the process of attaching the cover sheet 17 to the wallpanel substrate, and with the arrangement in the start positionillustrated by FIG. 8, the intermediate support 71 is moved downwardlyso as to lower the wiping devices 82, causing the wiping blades 84 to belowered from the raised position of FIG. 8 such that the protruding tip85 of each elastomeric wiping blade 84 contacts the adjacent edge flap18 generally at the upper corner-like edge 100 (FIG. 8A) of the panelframe, and then wipes downwardly, causing the end part of the blade todeflect and resiliently press the edge flap 18 against the end flange 16as illustrated in FIGS. 8A and 9. In this latter pressing position, thelowering motion of the intermediate support 71 is stopped. Since thisabove-described downward wiping of the blades 84 occurs simultaneouslydownwardly along the protruding edge flaps 18 adjacent opposite edgefaces of the workpiece 31, this hence effects initial tensioning of thecovering sheet as it is stretched transversely across the panel.

After stoppage of the opposed wiping blades 84 in the holding positionshown in FIG. 9, and as shown by dotted lines in FIG. 8A, the sweepingdevices 62 are then energized by first lowering the lower support 51 asmall amount so that the lower protruding tip ends 65 of the elasticsweeping blades 64 are moved into pressing contact with the up-facingfabric or cover sheet 17 at locations disposed adjacent but spacedinwardly from the adjacent lengthwise outer edge of the panel frame, asillustrated by dotted lines in FIG. 9. The sweeping blades 64 pressagainst the flexible cover sheet at a distance which is in theneighborhood of about one inch, or less, spaced inwardly from theadjacent panel edge. The downward movement of the lower support 51 isstopped when the tip ends of the sweep blades 64 make the desiredcontact with the up-facing covering sheet, whereupon the pressurecylinders 66 of both sweeping devices 62 are energized so that carriers63 and sweeping blades 64 mounted thereon, and disposed adjacentopposite sides of the workpiece, are simultaneously moved outwardlytoward the respectively adjacent frame edge. This results in the tipends of the elastomeric sweeping blades 64 creating sufficientfrictional engagement with the covering sheet to effect additionaltransverse tensioning thereof, with this tension being maintained whenthe sweeping blades reach a disposition directly adjacent the edges ofthe workpiece substantially as illustrated in FIG. 9. The extension orstroke of the cylinders 66, which can be adjusted to accommodatedifferent fabrics and different tension magnitudes, is then terminatedso that the sweeping blades 64 maintain their pressing contact with theflexible cover sheet to thus maintain the desired transverse tensioningthereof.

Thereafter the intermediate support 71 is lowered further downwardly,causing the carriers 83 and their respective wiper blades 84 to movedownwardly to a position substantially below the lower free end of therespective edge flaps 18 substantially as illustrated in FIG. 10. Thesweep blades 64, however, continues to maintain their pressingengagement with the upper surface of the cover sheet directly adjacentthe respective upper edge of the panel structure.

Upon reaching the lower position illustrated by FIG. 10, the motion ofthe intermediate support 71 is reversed so as to lift the carriers 83and wiping blades 84 upwardly. This causes the upper surface of thewiping blade to engage and lift the edge flaps 18 upwardly and, as thewiping blades 84 pass upwardly beyond the edge flange 16 of the panelstructure, the wiping blades cause the edge flap 18 to be deflected(i.e. wiped) upwardly along the vertical face 90 of the adjacent sweepcarrier 63. The upward movement of the wiper bar 83 is continued untilthe tip 85 of each wiper blade 84 is disposed in engagement with theupwardly-wiped edge flap 18 adjacent the upper free edge thereof,substantially as diagrammed in FIG. 11. With the edge flap 18 wipedupwardly and held in this upward extended position, the adhesiveapplicator device 105 is then utilized to apply adhesive to desiredareas of the edge flap and wall panel frame. Specifically, the elongatedrive unit 108 is energized which causes the spray nozzle 109 toprogressively move lengthwise along the raised flap 18 from one endposition (as indicated by solid lines 109 in FIG. 7) to the other endposition (as indicated by dotted lines 109 in FIG. 7). During thishorizontal traversing movement, the spray nozzle 109 emits a fan-shapedspray of adhesive which applies adhesive to the exposed back surface ofthe edge flap 18 at a location below the blade 84, and also appliesadhesive to the exposed exterior surface of the edge flange 16, as wellas into the interior of the groove 22. The spraying is suitablycontrolled by position sensors which sense the edges of the panel andappropriately turn the sprayer on and off when the leading and trailingedges of the panel are sensed during the traversing movement of thespray head, such sensors being well known.

Upon completion of the spraying operation, the intermediate support 71is again activated to effect slight upward movement of the carriers 83and blades 84 so as to cause the blades 84 to move upwardly out ofengagement with the edge flaps 18. During this latter upward movement,the entire device 82 can be slightly outwardly retracted (by energizingcylinders 92) a small distance if necessary or desirable so as toprevent undesired pulling on the free edge of the flap 18 as the blade84 is moved upwardly. After the upward displacement of blades 84 out ofcontact with the edge flaps, the latter will naturally fall downwardlyunder their own weight so as to hang generally downwardly past the edgeflanges 16 of the panel. The intermediate support 71 is then moveddownwardly (and the carriers 83 also moved inwardly if it was movedoutwardly as discussed above), whereupon the wiping blades 84 againmoves downwardly into contact with the upper longitudinal edge of thepanel frame, with further downward movement causing the blades 84 towipe downwardly along the edge flanges 16 to effect pressing of theadhesive-coated edge flaps 18 against the exterior surfaces of the edgeflanges 16. This downward movement continues until the blades 84disengage below the edge flanges 16, and the inserters 94 (FIG. 6) arealigned with the slots or grooves 22. At this position the intermediatesupport 71 is stopped, and the inserters 93 are slidably displacedhorizontally inwardly by activation of the pressure cylinders 95,whereby the tips 94 of the inserters engage the lower suspended parts ofthe edge flaps and insert them into the grooves 22, causing each edgeflap to come into contact with the adhesive-coated side walls of therespective groove 22, as illustrated in FIG. 14. The pressure cylinders95 are then reversely energized to withdraw the inserters 93, therebyleaving the edge flaps 18 adhesively secured to both the edge flange 16and to the groove walls, substantially as illustrated in FIG. 14. Thetackiness of the adhesive, and the speed with which it sets up, enablesthe edge flaps to remain securely joined to the edge frame members ofthe wall panel structure, whereupon the sweeping and wiping devices canthen be disengaged and retracted.

As to this latter disengagement, the carriers 83 and the respectivewiping blades 84 are preferably initially retracted sidewardly a smalldistance away from the panel by energizing the pressure cylinder 92 sothat the carrier 83 slides horizontally outwardly relative to the lowerend of the vertical support 86. Then the intermediate support 71 islifted upwardly to return the wiping blades 84 to their raised position,with the carriers 83 again being moved horizontally inwardly to assumetheir initial position of FIG. 8 by reverse energization of the pressurecylinders 92.

During the retracting of the wiping devices 82, the sweeping devices 62are also retracted by effecting upward lifting of the lower support 51so as to effect raising of the carriers 63 and blades 64, which upwardraising is accompanied by reverse energization of the cylinders 66 so asto retract the wiping blades inwardly back into the original position asillustrated by FIG. 8.

While the operation described above relates to the securement of a coversheet edge flap 18 having an inner part adhesively secured to a flatexterior surface 16 on the edge frame and also having a lower or freeedge part which is adhesively secured within a groove 22, as illustratedby FIG. 14, this being a replacement for the conventional constructionillustrated by FIG. 13, it will be appreciated that the presentinvention is equally applicable for permitting tensioning of the coversheet and adhesive securement of the edge flap solely to the flatexterior surface of the edge frame, such as the exterior surface of theedge flange 16 substantially as illustrated in FIG. 15. In thisvariation, a shorter cover sheet edge flap can optimally be used, oralternatively the groove can be eliminated and the surface contact areaon the edge flange increased. The operation otherwise corresponds tothat described above relative to the variation of FIG. 14 except thatutilization of the inserter 93 and the steps associated with activatingthe inserter are no longer required.

Considering a preferred construction of the sweeping blade arrangements,particularly as diagrammatically illustrated in FIG. 8A, the elastomericsweeping blade 64 is mounted on the carrier 63, confined between thecarrier and a face plate 90. The lower tip end part 65 of theelastomeric blade 64 typically extends or cantilevers downwardly beyondthe carrier 64 through only a small distance, such as about 1/16 inch toabout ¼ inch. This provides control over the blades and theircompressive engagement with the cover sheet, even when the blades aredisplaced sideward to tension the sheet, to minimize the potential ofdamaging the sheet.

As regards the wiping blade arrangement, however, the elastomeric wipingblade 84 is preferably mounted on the cover 83 such that the tip endpart 85 thereof protrudes or cantilevers horizontally outwardly througha greater distance, such as in the range of about ½ inch to about ¾inch. This permits the blade part 85 to initially engage the edge flap18 adjacent the upper edge or corner 100 of the end face, with thecontinued downward movement of the wiping blade causing the tip part toresiliently deflect so as to press the flap 18 against the edge surface16, as illustrated by dotted lines in FIG. 8A.

With the above features and properties of the wiping and sweepingblades, the opposite edge flaps can be simultaneously and uniformlytensioned and wrapped around the edge corners onto the edge surfacesthroughout the entire lengths thereof. Specifically, the resiliency ofthe wiping blades allows them to adjust to, and hence compensate for,any irregularities or distortions in the frame edge rails along thelength thereof, such as concave or convex distortions in directionsparallel to the plane of the workpiece or transverse thereto. Thisenables the cover sheet to be snugly engaged against the frame edge railso as to eliminate voids or pockets under the cover sheet due to theframe distortions which are normally present.

The sweeping blades 64 and wiping blades 84 are preferably constructedof a resilient rubber-like or elastomeric material capable of pressingand frictionally engaging the cover sheet, while at the same timeavoiding marking or damaging the cover sheet in contact therewith. Thetip ends can be provided with rounded corners or a curved exteriorconvex configuration to facilitate contact with the cover sheet, as wellas resilient deflection of the blade at the tip end. In addition, thewiping blades 84 may be slightly less stiff than the sweeping blades 64so that additional resiliency or elasticity more readily accommodatesengagement of the wiping blades with the frame during downward wipingengagement along the edge faces of the workpiece. This resiliency of thewiping blade also accommodates irregularities in the straightness of theworkpiece edge frame rail as well as irregularities or variations inthickness of the cover sheet. As exemplary, the wiping and sweepingblades can be constructed from elastomers having a durometer in therange of about 40 to about 60.

In addition, the stiffness of the sweeping blades 64 at the tip endsthereof, as achieved in part by the confined configuration thereof asdescribed above, enables application of significant downward contactpressure, specifically when the sweeping blades 64 are in the stop andclamp positions adjacent the edges of the workpiece frame, asillustrated in FIG. 9, which assists in straightening or at leastminimizing distortion of the elongate frame rails during the subsequentoperational steps of attaching the cover sheet edge flaps.

In performing the edge flap securing operation of the present invention,it will be recognized that the workpiece is initially be supplied to theapparatus 30 so as to permit securing of the edge flaps associated withone pair of opposed parallel side edges of the workpiece frame, andthereafter the workpiece may be supplied to a second similar apparatus30 so as to permit the edge flaps associated with the remaining pair ofparallel edges to be fixedly secured. In addition, since many fabriccover sheets have a greater amount of stretch or elasticity in onedirection in comparison to the other (i.e., transverse) direction, it ispreferable to first secure the edge flaps along the opposite paralleledges which extend generally parallel to the one direction (i.e., thedirection of most stretch or elasticity). Thereafter the edge flapsextending transversely (i.e., transverse to the most-stretch direction)of the fabric cover sheet are then secured, with the prior securement ofthe first edge flaps being effective in minimizing additional stretch ordistortion of the cover sheet.

In accordance with the process and apparatus of this invention, thesimultaneous tensioning and securement of edge flaps to oppositeparallel edge faces of the frame, which securement of the edge flapsalong the parallel edge faces occurs substantially simultaneousthroughout the length of the individual edge flaps, provides improvedcontrol and hence uniformity with respect to the tensioning of the coversheet during and after the securement thereof to the frame, and thusgreatly minimizes irregularities such as wrinkling or puckering of thecover sheet, such as frequently occurs when the securement of the edgeflaps is effected progressively along the length thereof in accordancewith known conventional techniques. The improved process and apparatusof this invention also provides satisfactory handling of the newerfabrics which have greater looseness of weave, greater elasticity and/orgreater slipperiness, while at the same time readily compensating forvarious thicknesses of fabrics.

It will be understood that the overall apparatus, including the variousdriving and sensing hardware, can be controlled using conventionalsystems, processors and/or computerized controllers.

It will also be appreciated that the process and apparatus of thisinvention can be readily accommodated into an automated assembly-lineprocess having automated conveying systems for feeding the workpieceboth into and out of the apparatus 30, with multiple similar apparatus30 being provided to permit sequential processing of parallel edge pairsassociated with one or both sides of the workpiece.

Although a particular preferred embodiment of the invention has beendisclosed in detail for illustrative purposes, it will be recognizedthat variations or modifications of the disclosed apparatus and process,including the rearrangement of parts and steps, lie within the scope ofthe present invention.

1. A process for securing a flexible cover sheet to a panel-shapedsubstrate, comprising the steps of: providing a workpiece defined by apanel-like substrate having a pair of generally parallel first edgefaces which extend generally perpendicular to and between a pair ofgenerally parallel second edge faces, and a thin flexible cover sheetpositioned in overlying and non-attached relationship to a large sideface of said substrate and having flexible edge flaps associated withand extending along each of said edge faces and protruding outwardlytherebeyond; providing a support having an upwardly-facing surfacedefining a generally horizontal working station adapted for supporting asaid workpiece thereon in a horizontal orientation; positioning ahorizontally oriented said workpiece on said working station with thecover sheet thereof facing upwardly and the edge flaps protrudingoutwardly of the respective edge faces of the workpiece; providing apair of vertically-movable wiping mechanisms positioned above saidworking station in sidewardly spaced relationship and generally abovethe respective first edge faces of the workpiece, and each wipingmechanism including an elastic wiping blade extending generally parallelto the adjacent first edge face throughout the length thereof, saidwiping blade projecting generally horizontally in a direction toward therespective edge face and terminating in a free end part; providing apair of vertically-movable sweeping mechanisms positioned above theworking station in sidewardly spaced relationship and generally abovethe respective first edge faces of the workpiece, and each sweepingmechanism including a sweeping blade which projects generally verticallydownwardly toward the workpiece disposed at the working station andwhich terminates in a free end part disposed upwardly over the workpieceat a location closely adjacent the respective edge face; moving saidwiping blades simultaneously downwardly from an initial raised positioninto contact with upper edges of the respective edge faces and the edgeflaps protruding outwardly thereof, and continuing the downward movementof the wiping blades so that the tip end parts of the wiping bladesengage the edge flaps and wipe them downwardly into pressed contact withrespective flat surfaces on the edge faces to effect tensioning of thecover sheet as it extends across the side face transversely between saidfirst edge faces; moving said sweeping blades simultaneously downwardlyfrom an initial raised position into pressing contact with an up-facingsurface of the cover sheet at locations adjacent the respective firstedge faces, and stopping the downward movement of the sweeping blades tomaintain a holding contact pressure on said cover sheet to maintain thetransverse tensioning thereof; then moving said wiping blades into aposition wherein they no longer press the edge flaps into contact withthe respective flat surfaces on the edge faces; then deflecting the edgeflaps upwardly into a raised position disposed above the flat surfacesof the respective edge faces; applying adhesive to said flat surfaces onsaid edge flaps and/or the back sides of the raised edge flaps, and thendisplacing the edge flaps so that they hang downwardly adjacent therespective first edge faces; then moving the wiping bladessimultaneously downwardly so that the free end parts of the wipingblades contact the respective edge flaps and press them into contactingengagement with the respective flat surfaces as the wiping blades movedownwardly of the first edge faces to adhesively secure the edge flapsto the respective flat surfaces of the first edge faces; and then movingsaid wiping blades and said sweeping blades back to their respectiveinitial positions.
 2. A process according to claim 1, wherein the stepof moving the sweeping blades downwardly into pressing contact with theup-facing surface of the cover sheet includes moving the sweeping bladesdownwardly into contacting engagement with the up-facing surface of thecover sheet and exerting a downward pressure thereon at respectivelocations spaced a small sideward distance from the respective firstedge face, then simultaneously moving the sweeping blades sidewardly inopposite outward directions to positions directly adjacent therespective first edge faces to effect final transverse tensioning of thecover sheet, and then maintaining contacting pressure on the cover sheetto maintain the transverse tensioning thereof.
 3. A process according toclaim 2, wherein the downward movement of the sweeping blades intopressing contact with the up-facing surface of the cover sheet occursafter the wiping blades have been moved downwardly to effect downwardwiping of the edge flaps into pressed contact with the respective flatsurfaces.
 4. A process according to claim 1, including moving the wipingblades downwardly past the flat surfaces to disengage the wiping bladesfrom the edge flaps after the sweeping blades have been moved intopressing contact with the up-facing surface of the cover sheet, and thenmoving the wiping blades upwardly deflecting the edge flaps upwardlyinto said raised position prior to the adhesive applying step.
 5. Aprocess according to claim 4, wherein the upward movement of the wipingblades causes the edge flaps to be lifted upwardly into a generallyvertical orientation adjacent a backing support, and then maintainingengagement between the free end parts of the wiping blades and upperfree end parts of the edge flaps to maintain them in said raisedposition, and thereafter spraying said adhesive lengthwise along theback sides of the raised edge flaps and also along the exposed flatsurfaces of the respective first edge faces.
 6. A process according toclaim 5, wherein the step of moving the sweeping blade downwardly intopressing contact with the up-facing surface of the cover sheet includesthe substeps of initially moving the sweeping blades downwardly intocontacting engagement with the up-facing surface of the cover sheet andexerting a downward pressure thereon at locations spaced a smallsideward distance from the respective first edge face, thensimultaneously moving the sweeping blades sidewardly in opposite outwarddirections to positions directly adjacent the respective edge faces toeffect final transverse tensioning of the cover sheet, and thenmaintaining contacting pressure on the cover sheet to maintain thetensioning thereof.
 7. A process according to claim 6, wherein thedownward movement of the sweeping blades into pressing contact with theup-facing surface of the cover sheet occurs after the wiping blades havebeen moved downwardly to effect downward wiping of the edge flaps intopressed contact with the respective flat surfaces.
 8. A processaccording to claim 1, including providing each edge face of theworkpiece with a channel-like groove opening outwardly of the edge faceadjacent an inner edge of the respective flat surface and extendinglengthwise along the edge face; providing each said edge flap with asufficient width to define an inner flap part which adheres to therespective flat surface and an outer flap part adjacent a free outeredge of the flap; and inserting said outer flap part into said grooveafter said inner flap part has been adhesively secured to the respectiveflat surface.
 9. A process according to claim 8, including applyingadhesive to each of the back face of the edge flap, the flat surface,and inner walls defining the groove when the respective edge flap is inthe raised position.
 10. A process according to claim 8, wherein thestep of moving the sweeping blades downwardly into pressing contact withthe up-facing surface of the cover sheet includes the substeps ofinitially moving the sweeping blades downwardly into contactingengagement with the up-facing surface of the cover sheet and exerting adownward pressure thereon at locations spaced a small sideward distancefrom the respective edge face, then simultaneously moving the wipingblades sidewardly in opposite outward directions to positions directlyadjacent the respective edge faces to effect final tensioning of thecover sheet, and then maintaining contacting pressure on the cover sheetto maintain the tensioning thereof; and the downward movement of thesweeping blades into pressing contact with the up-facing surface of thecover sheet occurring after the wiping blades have been moved downwardlyto wipe the edge flaps into pressed contact with the respective flatsurfaces.
 11. A process according to claim 10, including moving thewiping blades downwardly past the flat surfaces to disengage the wipingblades from the edge flaps after the sweeping blades have been movedinto pressing contact with the up-facing surface of the cover sheet, andthen moving the wiping blades upwardly so that the wiping blades liftthe edge flaps upwardly into said raised positions prior to the adhesiveapplying step.
 12. An apparatus for wrapping edges of a workpiecedefined by a panel-like substrate having an enlarged flexible coversheet freely overlying a side face thereof with the cover sheet havingflexible edge flaps which protrude outwardly beyond parallel edge facesdefined on opposite edges of the substrate, the edge faces of thesubstrate having exposed edge surfaces which project transverselyrelative to the side face of the substrate, said apparatus comprising: aframe; a support structure mounted on the frame and defining anupwardly-facing and generally horizontal planar support surface whichdefines a working station for permitting a workpiece to be supportinglypositioned thereof in a generally horizontal orientation; a cover sheetattaching arrangement vertically movably supported on said frame abovesaid working station for simultaneously securing opposite parallel edgeflaps of said cover sheet to respective parallel edge faces defined onopposite edges of said workpiece; said cover attaching arrangementincluding a pair of wiping devices disposed above the workpiecepositioned at the working station and disposed in sidewardly spacedrelation so that each said wiping device is positioned generally over arespective one of said parallel edge faces of said workpiece; each saidwiping device including a horizontally elongated elastomeric wipingblade positioned on a horizontally elongate vertically-movable carrierand extending generally parallel to the respectively adjacent edge face,said wiping blade projecting generally horizontally in a directiontoward the respective edge face and terminating in a free end partpositioned to engage the edge surface of the end face during downwardmovement of the wiping blade relative to the workpiece; a first drivedevice coupled to said pair of wiping devices for moving said wipingblades downwardly relative to the workpiece to cause the end parts ofthe wiping blades to engage the respective edge flaps adjacent upperedges of the respective edge faces and then wiping the edge flapsdownwardly into contact with the respective edge surfaces; said coverattaching arrangement also including a pair of sweeping devices disposedabove the workpiece positioned at said working station and disposed insidewardly spaced relation so that each said sweeping device is disposedover the workpiece close to a respective one of said parallel edgefaces, each said sweeping device being positioned closely adjacent arespective one of said wiping devices; each said sweeping deviceincluding a horizontally elongate elastomeric sweeping blade positionedon a vertically-movable carrier and extending generally parallel to therespectively adjacent edge face, said wiping blade projecting generallyvertically downwardly toward the upwardly-facing surface of the coversheet associated with the workpiece and terminating in a lower end partwhich is initially maintained in upwardly spaced relationship above thecover sheet; a second drive device coupled to said pair of sweepingdevices for effecting vertical movement thereof between raised andlowered positions, said second drive device effecting downward movementof said sweeping blades to cause the lower end parts thereof to moveinto pressing contact with the cover sheet at locations which aredisposed in close proximity to and extend generally parallel along therespective edge faces; whereby said sweeping blades when engaged withthe cover sheet adjacent the opposite parallel edge faces maintain thetransverse tensioning of the cover sheet while enabling the wipingblades to cooperate with the respective edge flaps.
 13. An apparatusaccording to claim 12, wherein each sweeping device includes a driveunit which effects generally horizontal sideward movement of thesweeping blade through a small distance after the sweeping blade isinitially moved into pressing contact with the cover sheet to effectfinal transverse tensioning of the cover sheet.
 14. An apparatusaccording to claim 13, wherein the first and second drive devices effectvertical displacement of the wiping and sweeping devices independentlyof one another, and wherein each sweeping device is coupled to therespectively adjacent wiping device through a vertical slide structureto permit relative vertical movement between the adjacent wiping andsweeping devices while maintaining the horizontal positionalrelationship therebetween.
 15. An apparatus according to claim 14,wherein the first drive device includes a generally vertically movablefirst support, and said pair of wiping devices being horizontallyslidably supported on said first support in sidewardly spacedrelationship and being slidably movable toward and away from one anotherto adjust to the width of the workpiece; and said second drive deviceincluding a generally vertically movable second support, and said pairof sweeping devices being horizontally slidably movably supported onsaid second support in sidewardly spaced relation to adjust to the widthof the workpiece.
 16. An apparatus according to claim 12, including anadhesive applicator arrangement coupled to each said sweeping device forvertical movement therewith, said adhesive applicator arrangementincluding an adhesive spray nozzle which moves lengthwise along therespective edge face of the workpiece for applying adhesive to the edgeface and to a back side of the respective edge flap.
 17. An apparatusaccording to claim 12, including an inserter blade carried on each saidwiping device and being horizontally movable for engaging and insertinga lower part of the edge flap into a groove which is formed in andextends lengthwise along the respective edge face.